title: Induced tRNA import into human mitochondria: implication of a host aminoacyl-tRNA-synthetase.
abstract: In human cell, a subset of small non-coding RNAs is imported into mitochondria from the cytosol. Analysis of the tRNA import pathway allowing targeting of the yeast tRNA(Lys)(CUU) into human mitochondria demonstrates a similarity between the RNA import mechanisms in yeast and human cells. We show that the cytosolic precursor of human mitochondrial lysyl-tRNA synthetase (preKARS2) interacts with the yeast tRNA(Lys)(CUU) and small artificial RNAs which contain the structural elements determining the tRNA mitochondrial import, and facilitates their internalization by isolated human mitochondria. The tRNA import efficiency increased upon addition of the glycolytic enzyme enolase, previously found to be an actor of the yeast RNA import machinery. Finally, the role of preKARS2 in the RNA mitochondrial import has been directly demonstrated in vivo, in cultured human cells transfected with the yeast tRNA and artificial importable RNA molecules, in combination with preKARS2 overexpression or downregulation by RNA interference. These findings suggest that the requirement of protein factors for the RNA mitochondrial targeting might be a conserved feature of the RNA import pathway in different organisms.
authors.affiliation: Department of Molecular and Cellular Genetics, UMR 7156 Génétique Moléculaire, Génomique, Microbiologie (GMGM), CNRS-Université de Strasbourg, Strasbourg, France.
authors.forename: Ali
authors.initials: A
authors.lastname: Gowher
authors.forename: Alexandre
authors.initials: A
authors.lastname: Smirnov
authors.forename: Ivan
authors.initials: I
authors.lastname: Tarassov
authors.forename: Nina
authors.initials: N
authors.lastname: Entelis
mesh_terms: D001483:Base Sequence; D027682:Cation Transport Proteins / Q000737:chemistry; D024202:Electrophoretic Mobility Shift Assay; D056945:Hep G2 Cells; D006801:Humans; D055029:Inverted Repeat Sequences; D008250:Lysine-tRNA Ligase / Q000737:chemistry / Q000378:metabolism*; D008928:Mitochondria / Q000201:enzymology* / Q000378:metabolism; D011485:Protein Binding; D011498:Protein Precursors / Q000737:chemistry / Q000378:metabolism; D034443:RNA Transport; D012331:RNA, Fungal / Q000737:chemistry / Q000378:metabolism; D012343:RNA, Transfer / Q000378:metabolism*; D012357:RNA, Transfer, Lys / Q000737:chemistry / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry
chemical_list: D027682:Cation Transport Proteins; D011498:Protein Precursors; D012331:RNA, Fungal; D012357:RNA, Transfer, Lys; D029701:Saccharomyces cerevisiae Proteins; C068664:TRK1 protein, S cerevisiae; D012343:RNA, Transfer; D008250:Lysine-tRNA Ligase